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M. Guillaud:
"Interference Alignment with Quantized Grassmannian Feedback for the K-user MIMO Interference Channel";
Talk: ETIS-ICI Seminar, Cergy-Pontoise, Frankreich (invited); 11-30-2012.

After recalling the definition and basic properties of the multiple-input multiple-output (MIMO) K-user interference channel, I will focus on the (now classical) technique of interference alignment (IA) and discuss its applicability when the channel state information (CSI) available at the transmitter is imperfect.
I will present recent work where a CSI feedback scheme based on quantization on the Grassmann manifold was introduced for IA-based transmission. The scaling with the transmit power of the number of feedback bits required to preserve the multiplexing gain that can be achieved under perfect channel state information is characterized. We demonstrate through simulation that the proposed scheme outperforms the naive feedback scheme consisting in independently quantizing the channel matrices, in the sense that it yields a better sum rate performance for the same number of feedback bits.

interference alignment, Grassmannian quantization, channel state information